1. Field of the Invention
The present invention relates to portable telephones and, particularly to a portable telephone having a movable portion.
2. Background of the Invention
A wide variety of radio communication system devices have hitherto been proposed to make a mobile communication. Radio communication system devices, such as mobile telephones, personal radio transceivers and portable telephones, in particular, of a stationary type, a shoulder type or a handheld type are now commercially available on the market.
FIG. 1 shows an example of a portable telephone that is now in general use. While personal transceivers make a communication by using the 90 MHz band, mobile telephones and portable telephones make a communication by using the 800 MHz band making antennas of the mobile telephone and the portable telephone relatively short in length.
In FIG. 1, reference numeral 1 generally depicts a portable telephone which is of a handheld type cordless telephone. As shown in FIG. 1, this portable telephone 1 includes an outer casing 2 of a rectangular box configuration made of synthetic resin. The outer casing 2 includes a front panel 2a, and the front panel 2a has a receiver or speaker 3 provided on its upper end face so as to be housed in the outer casing 2. The telephone 1 also includes an operation key group 4 disposed at its substantially central position. The operation key group 4 includes a plurality of operation keys, such as ten keys or the like. The telephone 1 includes a transmitter (microphone) 5 provided on its lower surface side so as to be housed in the outer casing 2.
The telephone 1 includes an antenna 6 upwardly extended from the upper surface portion of the outer casing 2. Some portable telephones include a liquid crystal display (LCD) unit provided on the front panel 2a of the outer casing 2 in order to display information entered by the user, though not shown.
The portable telephone 1 thus arranged includes the receiver 3 and the transmitter 5 both of which are housed within the outer casing 2. Therefore, the outer casing 2 has to be long enough to the extent that it can substantially cover the length between the user's ears and mouth. As a result, the whole portable telephone 1 becomes too large in size to be put into user's suitable carrying means, such as a purse or the like.
To solve the above-mentioned problem, proposed is a portable telephone which includes a telephone body composed of two telephone body portions joined by a hinge. These two telephone body portions are rotated to open when this portable telephone is in use.
Furthermore, there is commercially available a portable telephone having a miniaturized telephone body, i.e., a short-length outer casing. When this portable telephone is in use, a part of the outer casing can be slid upwardly along the longitudinal direction of the outer casing such that the length between the receiver and the transmitter housed in the lower portion of the outer casing can substantially cover the length between the user's ears and mouth.
However, as the outer casing of the telephone body is reduced in length, it is unavoidable that the antenna that is provided on the telephone body is placed closer to the user's body when the portable telephone is in use. When a telephone call is made, if the antenna of the portable telephone is placed too close to the user's body, then interference is exerted upon a radio radiation characteristic and a telephone call is disturbed by noise accordingly.